Methyl iodide → (R)-2-(Boc-amino)-4-pentynoic acid methyl ester

Participants

Reaction Steps

The commercially available compound, 2-(R)-tert-butoxycarbonylaminopent-4-ynoic acid (0.321 g, 1.50 mmol) was dissolved in anhydrous DMF (5 mL). To the solution was added cesium carbonate (0.54 g, 1.65 mmol) in one portion. The mixture was stirred at room temperature for 45 min before methyl iodide (0.20 mL, 3.00 mmol) was added, and further stirred for three hours. The reaction was quenched with water (10 mL). The organics was extracted with dichloromethane (2×30 mL), washed with water (3×50 mL), and dried over anhydrous sodium sulfate. The solvent was completely removed under vacuum. The residue was further dried under high vacuum over night and used in the next reaction without further purification. The product 23 was obtained as a colorless viscous oil (0.326 g, 95% yield). 1H NMR (300 MHz, CDCl3): δ 1.48 (s, 9H), 2.08 (t, J=2.6 Hz, 1H), 2.75 (t, J=6.3 Hz, 2H), 3.78 (s, 3H), 4.46 (m, 1H), 5.32 (br s, 5H).

Provenance & Evidence